This invention relates to polishing chucks, to semiconductor wafer polishing chucks, to abrading methods, to polishing methods, to semiconductor wafer polishing methods, and to methods of forming polishing chucks.
Polishing systems can typically include a polishing chuck which holds a work piece, and a platen upon which a polishing pad is mounted. One or more of the chuck and platen can be rotated and brought into physical contact with the other, whereby the work piece or portions thereof are abraded, ground, or otherwise polished. One problem associated with abrading, grinding or polishing work pieces in such systems, concerns uniformly removing or controlling the amount of material being removed from over the surface of a work piece.
Specifically, because of the dynamics involved in abrading work pieces, greater amounts of material can be removed over certain portions of a work piece, while lesser amounts of material are removed over other portions. Such can result in an undesirable abraded, ground, or polished profile. Yet, in other applications, it can be desirable to remove, somewhat unevenly, material from over certain portions of a work piece and not, or to a lesser degree over other portions of a work piece.
One challenge which has confronted those who process wafers is associated with retaining a wafer or work piece (which need not necessarily be a wafer), on the chuck when abrading or polishing the same. Because of the rotational velocities involved with such processing, the wafer can tend to slip off of the chuck during processing. One solution in the past has been to maintain vacuum pressure on the wafer during most or all of the processing of concern. That is, vacuum ports provided in the chuck to effect vacuum engagement of a wafer are essentially operated to maintain a vacuum relative to the wafer during abrading or polishing. However, such can cause dimpling of the wafer at these port locations which, in turn, can cause incomplete polishing of the wafer.
This invention arose out of concerns associated with providing improved uniformity in abrading, grinding, and/or polishing scenarios. In particular, this invention arose out of concerns associated with is providing uniformity and flexibility in the context of semiconductor wafer processing, wherein such processing includes abrading, grinding, or otherwise polishing a semiconductor wafer or work piece.
Polishing chucks, semiconductor wafer polishing chucks, abrading methods, polishing methods, semiconductor wafer polishing methods, and methods of forming polishing chucks are described. In one embodiment, a polishing chuck includes a body dimensioned to hold a work piece, and a multi-positionable, force-bearing surface is positioned on the body. The surface has an undeflected position, and is bi-directionally deflectable away from the undeflected position. A deformable work piece-engaging member is disposed adjacent the force-bearing surface for receiving a work piece thereagainst. The work piece-engaging member is positioned for movement with the force-bearing surface. In another embodiment, a yieldable surface is provided on the body and has a central area and a peripheral area outward of the central area. One of the central and peripheral areas is movable, relative to the other of the areas, to provide both inwardly and outwardly flexed surface configurations. A porous member is provided on the yieldable surface and is positioned to receive a work piece thereagainst. The porous member is preferably movable by the yieldable surface into the surface configurations. In yet another embodiment, a generally planar surface is provided on the body and positioned to receive the work piece thereagainst. The surface is movable into a non-planar, force-varying configuration in which more force can be exerted on outermost portions of a work piece during polishing than on innermost portions of a work piece. A deflector is operably connected with the surface and configured to move the surface into the non-planar configuration. A work piece-engaging expanse of material is positioned on the surface of the body and is movable thereby when the surface is moved into the non-planar, force-varying configuration.